It is essential that medical equipment that contacts semi-critical areas of the patient's body, such as mucous membranes or non-intact skin be clean and disinfected. Where the equipment is heat-sensitive, chemical disinfection or sterilization is required.
Dialdehydes, such as glutaraldehyde and ortho-phthalaldehyde, are known for their use in high-level disinfectant formulations for disinfecting medical equipment that contacts semi-critical areas of the patient's body. See, e.g., U.S. Pat. No. 4,851,449 (issued Jul. 25, 1989). Ortho-phthalaldehyde has broad-spectrum antimicrobial activity. Id.; U.S. Pat. No. 4,851,449. The FDA has cleared the ortho-phthalaldehyde disinfectant Cidex® OPA, which is now marketed commercially by Advanced Sterilization Products. Id. Cidex® OPA, comprises 0.55% ortho-phthalaldehyde, buffering agents, chelating agents and a corrosion inhibitor. See, Cidex® OPA Solution, 510(k) Summary of Safety and Effectiveness, K991487 (Oct. 6, 1999); see also, product literature at www.cidex.com. Other aromatic aldehydes also have antimicrobial activity, for example, U.S. Pat. No. 6,071,972, discloses disinfectant formulations comprising isophthalaldehyde or terephthalaldehyde, in a buffering system. And U.S. Pat. No. 5,223,166 (issued Jun. 29, 1993) discloses the use of disinfectant solutions comprising glutaraldehyde, glyoxal, malonaldehyde, and succinaldehyde.
Such dialdehyde compositions can be reused, but before such reuse, they must be tested to confirm that the minimum effective concentration of disinfectant is present. High quality and accuracy are desired. Further, equipment turn-around time is very important when considering methods for high-level disinfection and sterilization. Thus, test methods that determine disinfectant activity quickly are preferred.
In view of the foregoing, there is a need for devices and methods for fast, accurate determination of whether a minimum effective concentration of active ingredients is present in dialdehyde germicide compositions before reuse.